In recent years, research has been done on a system that connects a plurality of distributed power sources, such as solar cells and fuel cells, as power generation apparatuses, and supplies power generated by the power generation apparatuses. The power generation apparatuses used as these distributed power sources for example include fuel cells such as a Polymer Electrolyte Fuel Cell (PEFC) and a Solid Oxide Fuel Cell (SOFC). It has been proposed to adopt a plurality of such distributed power sources and control the power consumption of apparatuses constituting a load in accordance with the power that can be output by the distributed power sources.
Currently, power generated using a distributed power source such as the above-described fuel cell cannot be sold to the grid. Therefore, in current power supply systems, upon detecting reverse power flow to the grid of power generated by a distributed power source such as a fuel cell, control is performed to reduce or suspend the supply. Accordingly, in a system in which a plurality of these distributed power sources are connected and operate, the output of each of the plurality of distributed power sources is controlled upon detection of reverse power flow to adjust the power supplied by the system as a whole so that reverse power flow does not occur (for example, see JP 2002-247765 A (PTL 1)).